Help me understand auxiliary electrical systems...

[reaver]

So, in my quest to build my colorado into an off the grid expedition rig, I've been on a mission to gather at least a rudimentary understanding of vehicular electrical systems.

I know that drawing a map and planning things out is key to a successful build.

Eventual accessories include a winch, off road lights (light bar, various less for use in camp), fridge, multiple radios in the truck, an inverter and compressor in the bed, and probably an onboard water system, along with additional charging ports in the cab.

I know I'll need more powerful alternator and a better battery to keep this stuff running, but right now, I'm not necessary considering a dual battery setup due to space constraints.

Now, my main question is.... When doing this, do you generally splice directly into the +/- cables coming from the battery, and run that directly to the secondary fuse box, or do you clamp o to the battery terminals, or..... Is there another option?

 

[NapaTaco]

This how I’m running all my lights. This way I don’t do anything to my main fuse box and everything has it’s on fuse and it’s back up by a 100 amp inline breaker from the power lead. Got everything from amazon

 

[NapaTaco]

Here is what I bought

 

[1Louder]

You will need a deep cycle AGM battery. Probably something around 90 amp hour

You should put all of your accessories on a fuse block. Blue sea work well. I think it is better to have that in the vehicle so you only have to run 2 wires through the firewall. Then all of your radios, usb, fridge, whatever wiring stays in the cab.

Put some sort of cut off switch for said fuseblock near the battery.

Get solar to power all of this stuff when camped. 100 watt panel or better.

It really doesn't need to be that complicated. When you winch run the truck of course.

 

[slomatt]

Generally you run a new wire off the positive battery terminal. The new wire should have a properly sized fuse or circuit breaker located as close to the battery as possible. You can then run that wire to a fuse block (agree that Blue Sea is good quality) that is located either in the engine bay or in the cabin and use that to power your various loads.

Many people connect their winch directly to the positive and negative terminals on the battery. Personally I like to put a large fuse or circuit breaker on the winch's positive wire to protect from shorts that could happen if the wire rubs against a metal body part. Plus, you can then completely cut power to the winch if you are not going to be using it for a while.

 

[Road]

This how I’m running all my lights. This way I don’t do anything to my main fuse box and everything has it’s on fuse and it’s back up by a 100 amp inline breaker from the power lead. Got everything from amazon

Here is what I bought

I like that 100amp switch fuse. Looks like it might be handy for a number of things, not just stereo.

 

[phxdsrtrat]

I used a 300 amp marine bus fuse off of the terminal block on my battery for my winch. I also built out my accessory wiring based on this fuse/relay box. Made for a very clean install that is fully protected. I'm running a winch, auxilary lights, fridge and usb charging ports. They probably make larger versions of that fuse/relay box which may be what you need. If you don't need relays and are just looking for a fuse block I can't say enough good things about Blue Sea Systems. They have a wide variety of fuse blocks including one that I used in my trailer that attaches directly to the battery post.

-Curtiss

 

[reaver]

OK, so, fat positive wire coming directly to the fuse block off the battery.

Seems relatively simple.

I'm thinking relays will be the way to go for me. I can then toggle them using switches in the cab, to control the relays.

I guess I just need to map everything out, and come up with a game plan for what I want to do.

Now I need to figure out how to fit the truck with a higher power alternator, without frying my stock electronics.

 

[smritte]

Now I need to figure out how to fit the truck with a higher power alternator, without frying my stock electronics.

A higher output alternator will not fry anything. I see people say this on the internet all the time.
Here's how it works. You have Voltage and Current (amps).
Think of this like your garden hose. Volts=Pressure. Amps=volume. You have 100 psi and a hose with 1/2 inch diameter. You need more volume so you buy a 3/4 diamiter hose. The pressure is still 100psi.

The voltage is regulated to around 14 (ish) volts. This is a standard for all alternators (not military). If something is going to fry, the voltage needs to go over 15 volts. This happens with a broken regulator in the alternator.
The Current on the other hand has to be pulled from the alternator. Most modern alternators put out 14.5 volts and 100 amps. An upgraded alternator will be 14.5 volts and 200 amps. The voltage is the same. If your vehicle needs 50 amps, it doesn't matter what the max output is, it will only draw 50 amps.

I wont go into the different alternator designs. The newer alternators are better than the old school designs when it comes to high output. They are very expensive.
What you need to do is figure out how much current you already have and how much you need to pull when your done. To stay on the safe side you don't want to exceed 80% of your max. 100 amp alternator, 80 amp max draw. you can push it over that for short periods but the alternator gets a bit pissy about it.

When I calculate my draw I use a base of 25 amps for the vehicle (standard headlights low beam and wipers on low) and 40 amps battery. That gives me a baseline of 65 amps. Add in aux battery (40 amps), A few sets of off road lights (20 amps), fridge (7amps), over powered stereo amp obscenely loud (20 amps) = 152 amps with everything on. I would want 175-200 amp alternator.
If you don't speed through the desert at night with the stereo blasting then of course it would be lower. A 150 amp alternator covers almost all the applications we have. 65 amp base + 40 amp aux battery + 15 amp misc stuff= 135 amp draw.

 

[smritte]

OK, so, fat positive wire coming directly to the fuse block off the battery.

Don't forget the negative wire also. Electricity runs in a loop. If you need a big positive feed then you need a big negative feed also. Your entire vehicle is connected to the body for negative (ground) except the starter and the alternator. Those are connected to the engine. Your battery is connected to the engine and body. The cable going to the body is commonly too small to begin with. Even if you run all your pos and neg straight to the battery, you should upgrade your cable from the battery to the body (called body ground).

 

[madcratebuilder]

OK, so, fat positive wire coming directly to the fuse block off the battery.

Seems relatively simple.

I'm thinking relays will be the way to go for me. I can then toggle them using switches in the cab, to control the relays.

I guess I just need to map everything out, and come up with a game plan for what I want to do.

Now I need to figure out how to fit the truck with a higher power alternator, without frying my stock electronics.

You are not going to find a higher output for a 15' up Colorado, it's controlled by the ECM. I looked into it when I bought my ZR2. There is room for a side mounted battery under the washer bottle, you can replace a gas engine batt with the diesel version but you would only have one batt. A few guys have mounted under the bed along the frame rail. Info at Coloradofans.com.

 

[reaver]

You are not going to find a higher output for a 15' up Colorado, it's controlled by the ECM. I looked into it when I bought my ZR2. There is room for a side mounted battery under the washer bottle, you can replace a gas engine batt with the diesel version but you would only have one batt. A few guys have mounted under the bed along the frame rail. Info at Coloradofans.com.

I have an 04, so in my case, I can find a higher output alternator (up to 240 amps).

A higher output alternator will not fry anything. I see people say this on the internet all the time.
Here's how it works. You have Voltage and Current (amps).
Think of this like your garden hose. Volts=Pressure. Amps=volume. You have 100 psi and a hose with 1/2 inch diameter. You need more volume so you buy a 3/4 diamiter hose. The pressure is still 100psi.

The voltage is regulated to around 14 (ish) volts. This is a standard for all alternators (not military). If something is going to fry, the voltage needs to go over 15 volts. This happens with a broken regulator in the alternator.
The Current on the other hand has to be pulled from the alternator. Most modern alternators put out 14.5 volts and 100 amps. An upgraded alternator will be 14.5 volts and 200 amps. The voltage is the same. If your vehicle needs 50 amps, it doesn't matter what the max output is, it will only draw 50 amps.

I wont go into the different alternator designs. The newer alternators are better than the old school designs when it comes to high output. They are very expensive.
What you need to do is figure out how much current you already have and how much you need to pull when your done. To stay on the safe side you don't want to exceed 80% of your max. 100 amp alternator, 80 amp max draw. you can push it over that for short periods but the alternator gets a bit pissy about it.

When I calculate my draw I use a base of 25 amps for the vehicle (standard headlights low beam and wipers on low) and 40 amps battery. That gives me a baseline of 65 amps. Add in aux battery (40 amps), A few sets of off road lights (20 amps), fridge (7amps), over powered stereo amp obscenely loud (20 amps) = 152 amps with everything on. I would want 175-200 amp alternator.
If you don't speed through the desert at night with the stereo blasting then of course it would be lower. A 150 amp alternator covers almost all the applications we have. 65 amp base + 40 amp aux battery + 15 amp misc stuff= 135 amp draw.

This is an excellent, and easy to understand explanation of how it works. Thank you for that. I'll probably just go with a 200amp alternator then, without doing the math. I've not really decided whether I want to try and put a second battery in there, as I don't really understand the whole "isolator/dc-dc charger" thing yet. And, I can always add that later if need be. I honestly don't even need a fridge until I start going on trips lasting 5+ days or more.

 

[smritte]

If im not mistaken, you have a 100 amp in there now. If there was an option (towing package..) for a higher output factory alternator, that route is cheaper. Where you run into issues is when you start adding batteries. My cruiser has a 96 amp. Its fine for about everything I need. I just make sure my main battery is fully charged when I tow my trailer. It pushes the limit for a bit but, I'm still good.

 

[ChasingOurTrunks]

Great posts here with some solid info. I'm still learning about some aspects of this like DC to DC charging as that's fairly new to me, but before talking about amps and current, there is an important principle that I wish I knew when I first started doing electrical work:

Toyota/Jeep/GMC/Whoever know way more about making vehicle electrics than we do (mostly). Therefore, don't mess with their skills and experience -- do not "add" electric accessories. Add a secondary electrical system. This system should have as few connections to your vehicle electrics as possible -- ideally just two (+ and -). Every other thing you add should build off your secondary system.

There is a shockingly high number of Overlanding rigs (our old ones included) that have countless accessories that are piggybacking off fuses, tapped into wires, etc. With modern cars, this is an even greater risk as the voltages for components are very particular, and tapping into existing circuits can mess that up and throw codes that can interfere with the operation of the vehicle. By putting everything through your secondary system, you won't be stuck chasing an electrical gremlin that is stopping your car from working for 10 hours in the middle of nowhere all because you didn't install a component correctly and keep blowing the main fuse....don't ask me how I know that one!

If you are like me, this problem creeps over time -- you buy a piece of kit as you can afford it, wire it in, and then a few months go buy and another piece of kit, wired in, etc. If you START your electrical build with an secondary system, this piecemeal addition becomes easy. If you don't do it and say "ah it's just one fuse/wire/whatever", that will quickly become a half dozen fuses/wires/etc. and by then your wiring system will be severely compromised, and probably negate the value in a secondary system entirely.

 

[smritte]

There is a shockingly high number of Overlanding rigs (our old ones included) that have countless accessories that are piggybacking off fuses, tapped into wires, etc. With modern cars, this is an even greater risk as the voltages for components are very particular, and tapping into existing circuits can mess that up and throw codes that can interfere with the operation of the vehicle. By putting everything through your secondary system, you won't be stuck chasing an electrical gremlin that is stopping your car from working for 10 hours in the middle of nowhere all because you didn't install a component correctly and keep blowing the main fuse....don't ask me how I know that one!

Heh..welcome to my world. Chasing electrical ghosts for GM is what I did for 28 years. Gawd what I have seen people do. You nailed that one perfectly. Today everyone wants to jump into the "high tech gadget" world. A few years of vibrations later and the vehicle acts like its possessed. Good luck finding someone who is actually qualified to diagnose it. All my things keep to the KISS theory.

 

[Chetta58]

Secondary system is the way to go for sure. I tried out engineering the engineers for years and never once was I truly successful. It wasn’t until my wife got MS 17ish years ago that I stopped because she can’t walk out of some Backcountry mountain top and reliability of EVERYTHING became the priority.
There are a lot of versions of the self contained power/switch/fuse/relay all in ones and not all of them are that expensive and the S-POD is out of my price range . I paid less than 200$ for my setup with good components, wiring harnesses, switches, relays etc, have had it a couple years and use it darn near daily in my JK. The install took about an hour and done. It’s from Rugged Ridge and like any company they have items that are worthless and some that are actually pretty darned good. Mine is wired to my dual battery system and run completely off my aux battery w battery monitoring/voltage protection etc... I have an automatic so not being able to push start and being able to combine batteries with a push of a button was a ‘wife’ peace of mind deal more than a necessity but I’d never go back to a single setup. Anyway, just how I’ve done it and mho... good luck

 

[reaver]

If im not mistaken, you have a 100 amp in there now. If there was an option (towing package..) for a higher output factory alternator, that route is cheaper. Where you run into issues is when you start adding batteries. My cruiser has a 96 amp. Its fine for about everything I need. I just make sure my main battery is fully charged when I tow my trailer. It pushes the limit for a bit but, I'm still good.

I do in fact have a 100 amp alternator, currently. I've found a manufacturer that makes them all the way up to 240 amps. That's probably overkill for my needs. 200 is probably overkill as well, but I don't want to have to buy a third alternator if I decide to add a second battery.

Great posts here with some solid info. I'm still learning about some aspects of this like DC to DC charging as that's fairly new to me, but before talking about amps and current, there is an important principle that I wish I knew when I first started doing electrical work:

Toyota/Jeep/GMC/Whoever know way more about making vehicle electrics than we do (mostly). Therefore, don't mess with their skills and experience -- do not "add" electric accessories. Add a secondary electrical system. This system should have as few connections to your vehicle electrics as possible -- ideally just two (+ and -). Every other thing you add should build off your secondary system.

There is a shockingly high number of Overlanding rigs (our old ones included) that have countless accessories that are piggybacking off fuses, tapped into wires, etc. With modern cars, this is an even greater risk as the voltages for components are very particular, and tapping into existing circuits can mess that up and throw codes that can interfere with the operation of the vehicle. By putting everything through your secondary system, you won't be stuck chasing an electrical gremlin that is stopping your car from working for 10 hours in the middle of nowhere all because you didn't install a component correctly and keep blowing the main fuse....don't ask me how I know that one!

If you are like me, this problem creeps over time -- you buy a piece of kit as you can afford it, wire it in, and then a few months go buy and another piece of kit, wired in, etc. If you START your electrical build with an secondary system, this piecemeal addition becomes easy. If you don't do it and say "ah it's just one fuse/wire/whatever", that will quickly become a half dozen fuses/wires/etc. and by then your wiring system will be severely compromised, and probably negate the value in a secondary system entirely.

I 100% agree with you here. Fortunately, I have not touched my stock electrical system. My radios run of a 12v splitter that also charges my phone, which is plugged into the accessory port on my dash. That's the extent of my modifications so far. Anything I add past that will be on a secondary system.

I guess the question now is what's the best way to hook up and charge a secondary battery? Isolator, DC to DC, or directly off the alternator?

 

[eagle_A40]

This is what I'm working on at the moment.

10 ga. power wire will run from the Positive battery terminal, to the 100 AMP breaker.
10 ga. power wire will leave the breaker and run to the 100 AMP Relay.
10 ga. power wire will run from the relay, to the auxiliary fuse panel inside the cab(the fuse panel can also be mounted under the hood).
The 100 AMP relay will be energized by two 12 ga. wires(1 Pos., 1 Neg.). The Pos. will be supply power to the Relay, from the ignition circuit. The Neg. will be grounded to the engine/frame. When the ignition switch is turned ON, it will energize the relay and send power to the auxiliary fuse panel.



See auxiliary fuse panel below:
RED from designated fuse, to supply power to Relays.
Black from Fuse Block(negative terminals), to Relays.
YELLOW from white Terminal Bar to the Relays. This will switch the Relays ON or OFF.
BLUE to supply power, from Relay to the Accessories(lights, etc.)

Not shown: Power(Control) wire from the switch bank will run to the opposite side(top) of the white terminal bar. See lower drawing.



This drawing may help.

 

[reaver]

Out of curiosity, why are you running it this way? Let's say you've got a fridge on that secondary system. Does that mean unless the ignition is on, there's no power running to the fridge?

 

[eagle_A40]

Out of curiosity, why are you running it this way? Let's say you've got a fridge on that secondary system. Does that mean unless the ignition is on, there's no power running to the fridge?

Sorry, it's not shown in the drawings, but a guarded switch will be located in the cab, to supply power to the 100 AMP relay, to bypass the ignition feed when needed.